We report on single-crystal growth, crystal structural determination and magnetic, electrical resistivity and thermoelectric power measurements performed on a set of single crystals of U 3 Rh 3 Sb 4 . The compound crystallizes in the cubic Y 3 Au 3 Sb 4 -type structure. The ac susceptibility and dc magnetization both indicate that the compound undergoes a transition into a spin-glass state below 14.7 K. The resistivity shows a broad minimum at 30 K. The thermoelectric power is negative in the whole temperature range studied and exhibits an enhanced value of −32 µV K −1 at room temperature.